Automatic gun control system



1951 w. H. NEWEQLL ETAL 2,569,571

AUTOMATIC GUN CONTROL SYSTEM Filed May 5, 1944 14 Sheets-Sheet 1INVENTORS WILLIAM H. NEWELL JAMES D. TEAR fAWRW/OW ATTORNEY.

Oct. 2, 1951 w. H. NEWELL EI'AL AUTOMATIC GUN CONTROL SYSTEM 14Sheets-Sheet 2 Filed May .5, 1944 8L a Y 0 0 TwR E EA N ENES R 5+ m N .T[M N A MMW WM 2, 1951 w. H. NEWELL EI'AL 2,569,571

AUTOMATIC GUN CONTROL SYSTEM Filed May 5, 1944 14 Sheets-Sheet 5INVENTORS WILL/AM H. NEWELL JAMES 0. TEAR LAWREN E BROWN Zazr-r ATTORNEY0d. 2, 1951 w L ETAL 2,569,571

' AUTOMATIC GUN CONTROL SYSTEM Filed May .5, 1944 14 Sheets-Sheet 4INVENTORS WILLIAM H. N'EWE'LL JAMES D. TEAR V AWRENCE 5. BROWN MATTORNEY Oct. 1951 w. H. NEWELL ETAL AUTOMATIC GUN CONTROL SYSTEM 14Sheets-Sheet 5 Filed May 5, 1944 2, Q n a m9 8m if. m2 Q9 m2 1 11 m :1 09 09 5. 3 Ni Q n: 31 09 m. 31 Q1 IN VE N TOR6 WILL/AM H.NEWELL JAMES a.TEAR LAWRENCE 5. R0 WN ATfORNEY Oct- 1 5 w. H. NEWELL EIAL AUTOMATIC GUNCQNTROL SYSTEM 14 Sheets-Sheet 6 Filed May 5, 1944 ELL ROWN M WILLIAMJAMES D. LAWREN/(F.

ATTORNEY Oct. 2, 1951 w. H. NEWELL ETAL AUTOMATIC GUN CONTROL SYSTEM 14Sheets-Sheet '7 Filed May 5, 1944 no n mow 5L N Ram Y mm m M uns R MHisVm NM m mT A M WMM 14 Sheets-Sheet 8 Filed May 5, 1944 L N 5 RB m Y w M EB NE P E T 0 Wu W m m A ER my WJL 2, 1951 w. H. NEWELL ETAL 2,569,571

AUTOMATIC GUN CONTROL SYSTEM Filed May 5, 1944 l4 Sheets-Sheet RECESSIONRA INPUT T0 COMPUTER RATE AMPLIFIER VALVES US P0 P2 D5 6 v vt CONTROL &VALVES PREGESSING PRESSURE GENERATING VALVES.

ELEVATION HYD. MOTOR TRAN HYD. MOTOR P2 Ve 62 TRAIN MOTOR CONTROL BLOCK65 ELEVATION CONTROL BLOCK IN VEN TORS WILLIAM H. NEWELL JAMES B. TEARLA WRENCE 8. BROWN ATTOkNEY 1951 w. H. NEWELL ETAL 2,569,571

AUTOMATIC GUN CONTROL SYSTEM Filed May 5, 1944 14' Sheets-Skeet 12 INVEN T0 RS WILLIAMH. NEWELL JAMES D.TEAR

LA WRENCE 5. BROWN ATf'ORNEY 5 1951 w. H. NEWELL ET AL 2,569,571

AUTOMATIC GUN CONTROL SYSTEM Filed May 5, 1944 l4 Sheets-Sheet 15 sesaabfl INVENTORS WILL/AM H.NEWELL JAMES D.TEAR LAWREN E5 BROWN "r0 TRAlNHYD. MOTOR o m V 88 tg uokow ATTORNEY Oct. 2, 1951 w. H. NEWELL ET ALAUTOMATIC GUN CONTROL SYSTEM 14 Sheets-Sheet 14 Filed May 5, 1944 0w m Ens N mwms .R Z w NMO.N T maf A MM I WJLV n I I n I n n I n I I u I I I nn I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I nPatented Oct. 2, 1 951 UNITED STATES PATENT OFFICE AUTOMATIC GUN CONTROLSYSTEM William H. Newell, New York, James D. Tear, Great Neck, andLawrence S. Brown, Long Island City, N. Y., assignors to The SperryCorporation, a corporation of Delaware Application May 5, 1944, SerialNo. 534,330

7 Claims. 1

This invention relates to automatic gun control systems of the type inwhich a gun mount is driven in response to movement of a precessedgyroscope at controlled rates of train and elevation and the gun isautomatically given a lead or deflection with respect to the line ofsight, both in train and in elevation, which is a function of the range,the speed of the observer and the rates of train and elevation.

More particularly, the system includes a sighting mechanism controlledby the gyroscope to maintain the line of sight parallel to the spin axisof the gyroscope. Precessing forces are set up by the observer or gunnerand applied to the gyroscope to maintain the sight on the target. Theseprecessing forces, which determine and are proportional to the rate ofthe gyroscope, are also set into an automatic computing mechanism theoutput of which controls the deflection between the sight and the gun.

The gunner also actuates a range finding mechanism connected to set intothe automatic computing mechanism the range, which at the short rangesof aircraft guns for example, is assumed to be proportional to the timeof flight. In one embodiment this range finding mechanism is operated bya pair of foot pedals which are connected for opposed movement so thatwhen one pedal moves upwardly the other pedal moves downwardly. In thisway the effect of jolts or bumps is eliminated and a more accurate anddependable control of the range input is obtained.

The range finder mechanism includes a divider which automaticallydivides the size of the target by the range set into the computingmechanism by the operation of the foot pedals. The output of the dividerrepresents the angle subtended by the target at the set range. The sizeof the target is introduced by a manual setting. The speed of theobserver or of the gunners own ship is set into the automatic computingmechanism by a manual adjustment.

The outputs of the automatic computing mechanism representing sightdeflections in train and elevation are connected to modify the action ofa follow-up mechanism which controls the elevation and train motors ofthe gun mount to maintain the gun at the required firing angle.

As applied to a bomber turret for example, a control handle isaccessible to the gunner while in sighting position in the turret and isconnected to control the precessing forces so that the gunner merelyactuates the control handle in a manner to keep the line of sight on themoving target, and the range finding mechanism in a manner to maintaincorrect range adjustments. The automatic computing mechanism thenoperates to set the required deflection or lead into the follow-upmechanism which automatically keeps the guns at the correct firingangle.

An object of this invention is to provide a mechanism of the above typehaving novel and improved details of construction and features ofoperation.

Another object is to provide a system of the above type which is suitedto production and operation under military conditions.

Another object is to provide a system of the above type which is of wideapplication to various types of turrets on shipboard, planes, landvehicles, fixed anti-aircraft guns and the like;

Other objects and advantages will be apparent as the nature of theinvention is more fully disclosed.

In accordance with the present invention a hydraulic system is providedfor applying the precessing forces to the gyroscope, for setting therates of elevation and train into the computing apparatus and fordriving the gun mount or turret in accordance with the position of thegyroscope and the output of the computer; This hydraulic system includesa pair of pressure control valves actuated in accordance with theposition and rate of movement of the gunners control handle to generatecontrol pressures corresponding to the desired rates of train andelevation respectively. These control pressures are applied directly toprecessing force motors which apply precessing forces to the gyroscope,and are also applied through hydraulic rate amplifier valves to rateinput linkages of the automatic computing apparatus.

Control valves actuated by the gyroscope are connected to control thehydraulic follow-upapparatus which drives the gun mount or turret. Theautomatic computing apparatus sets the deflection into the control valvemechanism so that the position taken by the gun mount or turretcorresponds to the angle of the gyroscope or sight plus the computeddeflection by which the gun must be deflected from the line of sight.

The range is set into the computer from a range finding mechanism whichis adjusted manually in accordance with the known size of the target andthe range. The range finding mechanism is adjusted to position the rangedetermining member of a range finder such as an iris diaphragm, which ismaintained by the gunner at a size to just encompass the target. The

range finder may be actuated by a foot control so that the gunner canactuate the same continuously while causing the sight to follow thetarget by means of his hand control. These are the only manualoperations required of the gunner apart from an initial setting of thespeed of his own ship and pressing the firing button when the guns areto be fired.

In a system of this type the gunner may ride in the turret or thetracking, range finding and computing mechanism may be. located at .a.remote point as in a director. With this arrangement, several gun mountsmay be operated in unison by the same director.

Although the novel features which are believed to be characteristic ofthis invention are pointed out more particularly in the claims appended.

hereto, the nature of the invention will be better understood byreferring to the following descrip-- tion, taken in connection. with theaccompanying drawings in which a specific. embodiment thereof has beenset forth, for purposes of illustration.

In the drawings, 7

Fig. 1 is a vertical section through a gun turret showing. the controlmechanism in front elevation;

Fig. 2 is a side elevation of the controlmechanism shown in Fig. 1;

Fig. '3' is a top plan view thereof;

Fig. 4 is a side elevation of a control box. and associated mechanism;

Fig. 5 is a diagram of the computing mechanism;

Fig. 6 is a diagram of the gyroscope and gyrocontrol mechanism includingthe range finder and sighting mirror;

Fig. 7 is a front elevation of the control box with the cover removed toshow the mechanism therein;

Fig. 8 is a side elevation of the mechanism within the control box;

Fig. 9 is a plan view thereof; a

Fig. 1.0 is a diagram of the hydraulic system;

Fig. 11 is a section through the hydraulic control pressure valve blockshowing the control handle and the hydraulic connections;

Fig. 12 is a side elevation of the manual control handle and supporttherefor;

Fig. 13 isa vertical section through the control handle and support;

Fig. 14 is a sectional view through the rate amplifier valve block, thespiral follow-up valve block, and the processing motor block, showingthe hydraulic connections;

Fig. 15 is a sectional View through the pump block of the variable speedhydraulic transmission showing the. control valves. and the hydraulicconnections Fig. 16 is a plan view of the range foot pedal on the left.ofthe operator and its frame. connection;

Fig. 17 is a side elevation of the mechanism shown in Fig. 16 showingits. gear connections; and

Fig. 18 is a plan view partly in section of the operators. hand controlvalve mechanism taken on line I8I8 of. Fig. 11.

Certain specific terms are used herein for convenience in referring tovarious details of the invention. These terms, however, are to be. givenan interpretation commensurate with. the state of the art.

Referring to Figs. 1, 2 and 3,.the mechanism is shown as comprising, apair. of guns I0 and II carried in cylindricalgun mounts I2 and. I3respectively which are pivoted for movement in elevation about outerhorizontal trunnions I4 and I5 respectively and inner horizontaltrunnions I6 and I1 respectively. The outer trunnions I4 and I5 arecarried by outer brackets I8 and I9 respectively. The inner trunnions I6and 1T are carried by inner brackets 20 and 2| respectively.

The gun mounts I2 and I3 are adjusted in elevation by means of gearsmounted upon an. elevation shaft 26 and engaging circular racks 21 onthe gun mounts I2 and I3. The elevation shaft 26 carries a gear 28 whichis driven by a pinion 23*; actuated by a hydraulic motor 30 mounted .ona support 32 which extends between theinne-rbrackets 20 and 2 I. Theelevation shaft 7 26v is mounted in brackets 3! attached to the support32.

Acontrol box containing the automatic computing mechanism, the;gyro-control mechanism and the range finder, all to be described, ismounted on brackets M and 42 (Fig. 3), which are journalled in trunnions43 and 44 respectively carried by the inner frame members 23 and 2I. Thebox 40 is constrained for .movement in elevation with the gun mounts I2.and I3 by a pair of linkages comprising links 45 pivotally mounted bypins 46 to the gun mounts I2 and I3 and telescoping into links 41 whichare pivoted at 43 to the brackets II and. 42. The links 45 are latchedto the links 41 by pins 49' (see .Fig. 4') which may be withdrawn topermit the links 45 and 4! to be separated so: as to disconnect the box40 from the gun mounts I2v and I3. The box 40 is counter-balancedbysprings 53 connected between the pins 54 on the brackets 4I and 42 andstationary pins 54a. carried by the inner brackets 20 and 2|. v 1

Referring to Fig. 4, the pin 49 is shown as mounted in a bracket andheld downwardly by a pressure spring. 5 I. The pin is provided with aknob 52 to provide manual. means for withdrawing the pins to disconnectthe links 45 and 41 as above mentioned.

Referring again to Fig. 1, a pair of contro handles 55 are mounted on ahorizontal shaft 400, journalled in a bracket 56 which is mounted forrotation about a vertical axis on a block 51 (Figs. 1 and 11)containingthe hydraulic pressure control valves to-be described forcontrolling the processing pressures. The block 5'! is mounted on abracket 56 (Figs. 1,2 and 3)- which is attached to a transverse plate 59extending between the inner brackets 20 and 2|.

The transverse plate 59- also carries a pump block 66 (Figs. 1, 10 and15) on which the main motor 6I is mounted and to which'valve blocks 62and 63 are connected... The valve blocks 62 and 63 control the supply offiuid from the pump to the hydraulic elevation motor 30 and to ahydraulic train motor 65 (Fig. 1) driving a gear 66 which cooperateswith a rack 6! on a stationary frame ring 68. The train motor 65 ismounted on a bracket I6- which is attached to the frame II of themovable turret. The frame II supports the outer brackets I8 and I9 andcarries cross beams I2 which support the inner brackets 26 and 2| andthe transverse plate 59. The frame II incl des an outer annular memberI5 carrying rollers I6 which engage in an annular track I! on thestationary frame ringv 68. The train motor 65 causes the entire turretto rotate inside the track 11. A seat for thev gunner is mounted onbrackets 8I, Figs. 2 and 3, attached tqt e cro sa .2-

The general arrangement of the apparatus so far described is such thatthe gunner rotates the handles 55 about a horizontal axis in accordancewith variations in elevation to be applied to the sight for causing itto follow the target in elevation and rotates the bracket 59 about itsvertical axis in accordance with variations in train which are to beapplied to the sight. This rotation of the handles 55 actuates suitablevalves within the valve block to generate pressures which areproportional to the amount and rate of movement of the handles 55 intrain and in elevation. These pressures are applied to hydraulic controlmechanism within the control box 49 as precessing forces to cause thegyroscope to precess in the desired direction and at a rate dependingupon the precessing forces. The precessing pressures also actuate therate input linkages of the automatic computing mechanism within thecontrol box 40.

These precessing forces then cause the gyroscope and the sight which isassociated therewith to move in train and in elevation as desired. Thismovement of the gyroscope in turn actuates the spiral follow-up valvemechanism within the control box 49 to control the valves Within thevalve blocks 62 and 63 so as to cause the pumps within the pump block 99to supply fluid at controlled rates to actuate the elevation motor 39and the train motor 95. The automatic computing mechanism automaticallysets into the follow-up valves the proper deflection so that the gun iscaused to be displaced from the line of sight in train and elevation thecorrect amount for causing the projectile to hit the moving target.

Computing mechanism Referring now to Figs. 4, 5 and 7-9, the computingmechanism is shown as of the general type disclosed in the co-pendingapplication of James D. Tear and Charles W. Buckley, Ser. No. 375,426,filed Jan. 22, 1941, for Gun Sights, and now Patent No. 2,407,191. Inthat application it is shown that the total deflection of the guns fromthe sight in train and in elevation may be represented by the followingformulae:

(1) Ds=T (dBsK1S0 sin Bg+7c2 (2) Us=T (dE-K3So cos Bg sin Eg+7c4)wherein Ds represents the deflection of the gun in train with respect tothe sights. T represents the time of flight; dBs represents the bearingrate or the rate of train; So represents the speed of the observers ownship; Bg is the bearing of the gun; 03E represents the rate ofelevation; By the angle of elevation of the gun; Us the requiredelevation of the gun with respect to the plane of the sight or thedeflection in elevation; and K1, k2, K3 and k4 represent constants.

The constants Kl, k2, K3 and k4 are taken care of by the selection ofthe gears in the computing mechanism. These constants may be eliminatedfrom the equations which may then be written as follows:

(3) Ds=T (dBs.S'o sin'Bg) (4) Us=T (dESo cos Bg sin Eg) Equations 3 and4 therefore represent the equations which must be solved by theautomatic computing mechanism in order to arrive at the deflection intrain Ds and the deflection in elevation Us which must be set into thefollow-up valves.

Referring now to Fig. 5, the computing mechanism is shown as comprisinga train disc 99 which is angularly adjusted in accordance with thebearing of the gun Bg by a gear 9| meshing with teeth 92 of the traindisc 99 and'carried on a shaft 93 which is driven through bevelled gears94 by a tram shaft 95. The train shaft 95 is driven through bevelledgears 96 by a flexible train shaft 91 which, as shown in Figs. 1 to 4,is located on the outside of the control box 49 and is driven throughbevelled gears 99 from a shaft 99 carrying a pinion I99 meshing with thestationary rack 61 on the frame ring 59. The free end of the flexibleshaft 91 and the shaft 99 are mounted on a bracket I92 which is attachedto the frame 'II of the turret and rotates therewith, so that the trainof the turret, which corresponds to the bearing of the gun Bg, is fed bythe shaft 97 into the train shaft 95 of the computing mechanism andcauses a corresponding rotation of the train disc 99.

A train dial I95, mounted on a shaft I96, is driven from the train shaft95 through a worm I0! and worm gear I98. The train dial I95 is mountedto be visible from the front of the box 49 as shown in Fig. 1.

The speed of the observers own ship (So) is the vector represented bythe radial distance of a pin H9 from the center of the train disc 99.

This radial distance of the pin II 9 is controlled by a spiral groove ina speed disc III which is mounted concentric with the train disc 99 andis rotated with respect to the train disc by a pinion I I2 engagingteeth II3 on the periphery of the speed disc II I and mounted on a shaftII i which is driven through bevelled gears II5 by a shaft IIB which isconnected to one side of a differential I H. The other side of thedifferential II! is driven by a shaft II8 which connects throughbevelled gears H9 with a shaft I29 which is controlled by a speedcontrol knob I2I mounted in accessible position on the outside of thebox 49 as shown in Fig. 1. A speed dial I22 is mounted on a shaft I23carrying a gear I29 meshing with a gear I25 which, in turn is driven bya gear I29 on the shaft I29. The speed dial I22 is likewise mounted in aposition to be observed from the front of the box 49.

In order to prevent adjustment of the train disc 99 from changing therelative position of the train disc 99 and the speed disc III, acompensating connection is provided comprising a shaft I39 driventhrough bevelled gears I3I from the train-shaft 95 and carrying abevelled gear I32 which drives the housing of the differential II I sothat movement of the train shaft 95 causes adjustment of the train disc99 and speed disc I I I in unison, whereas adjustment of the speed shaftII8 causes relative movement between the train disc 99 and the speeddisc III for adjusting the radial position of the pin I I9.

The pin II9 actuates a sine rack I49 and a cosine rack I4I which are ofstandard construction. The movement of the sine rack I49 thus representsSo sin Bg whereas movement of the cosine rack I4I represents So cos Bg.Motion of the sine rack I49 is transferred to the input of adifferential mechanism I42 by a gear train comprising pinion I I3, shaftI44, bevelled gears I45, shaft I46, bevelled gears I91, shaft I 48,pinion I49 and rack I59. The rack I59 is pivoted to an arm I5I whichforms a part of the differential mechanism I42.

The rate of train dBs is fed into the differential mechanism I42 by alink I55 actuated by a hydraulic rate amplifier valve mechanism to bedescribed, so as to have a longitudinal movement amen-'21 proportionalto the rate of train. Thisel-ink. I55 is connected by a pin I56 to thearm I5I as the second input to the differential I42. An intermediateportion of the arm I5I is pivoted by a pin I51 to a link I58 whichactuates the arm I59 which turns about a fixed pivot I6I. The movementof the arm I59 accordingly corresponds to the differential movement ofthe two ends of the arm I5I, so that its angular position representsdBsSo sin B9.

The time of flight (T) is set into the computing apparatus by a rangeshaft I60. Range shaft I60 carries a pinion I 6! driving a rack I62which actuates a range finding mechanism to be described. The range ismanually set into the shaft I60 by a rang-e tape I65 actuated by meansto be described, which engages a range pulley I66 connected to drive oneside of a differential I61. The other side of the differential I61carries an elevation pulley I68, driven by an elevation tape I69 in amanner to compensate for movement of the. range tape I65 produced bymovement in elevation of the box 40.

The range shaft I68 drives the range. dial I12, mounted on a shaft I13carryin a worm gear I114 which is driven by a worm I mounted on theshaft I60. The range dial I12 is mounted on. the front of the box 48 asshown in Fig. 1.

The range shaft I69 drives bevelled gears I16 which drive a shaft I11carrying a pinion I18 meshing-with a rack I19 forming one input to amultiplier I80. The second input to the multiplier I80 is the pivotedarm I59 above mentioned which carries a pin I8I slidably mountedthereon. The rack I19 carries a T-arm I82 having a slot I83 in. whichthe pin I8I slides. The output of the'multiplier I86 comprises a rackI84 having an L-arm I85 provided with a slot I66 in which the pin I8Islides. The movement of the. rack I84. accordingly represents theproduct of the inputs from the pivoted arm I59 and the rack I 19 orT(dBs-So sin Bg) which from Equation 1 is seen to represent thedeflection Ds. This movement is transferred by a pinion I90 and shaft I9I through a. gear train comprising bevelled gears I92, shaft I93 andbevelled gears. I94, to a shaft I95 which is connected to the hydraulicspiral follow-up valve to be described. The movement of the shaft I95thus represents the computed horizontal deflection Ds by which the gunmust be offset. from the line of sight.

The range tape I65, as shown in Fig. 4, passes around idler pulleys I98and engages a pulley I99 which is loosely mounted about the trunnion 44.A second idler pulley 200, which is attached to the first; idler pulleyI99, is engaged by a; belt I passing around a belt pulley 282 which, asshown in Fig. 1, is mounted on a bracket 203 carried by the innerbracket 2|. The belt pulley 202 is operated by a link 204 which ispinned to the pulley 262 by a pin 205. The link.204 engages a bell cranklever 206 (Figs. 1 and 2) which is mounted on the inner bracket 2| andis actuated by' a link 201 attached to a foot pedal 208 in a position tobe operated by the foot of the gunner. A pair of foot pedals 208 and 209are shown in Figs. 1, 2 and 16 and 17 which are connected by a shaft 2I0 and gears 2 I l to be actuated in opposite directions so that as onefoot is elevated the other foot is depressed. In this way an accuratecontrol is obtained as the operation of the foot pedals is notinfluenced by the jars to which the gunner may be subjected. The rangetape or belt I65 is thus operated through. the linkages above mentionedby the foot pedals 208 and 209 by anamountwhiohthegunner determines fromthe range findento bedescribed, Which is operated by the rack I62.

Elevation is fed into an elevation shaft 226 by an elevationpulley 22Iactuated by the elevation tape-I69. Thertape I69. passes around thepulley 222 whichis concentric with pivot 48 and is fixed to the link 41(Fig. 4) to. be actuated by pivotal movement of said link.

I The elevation shaft 220 connects through bevelled gears 225 and shaft226 to a pinion. 221 which actuates an elevation disc 228 carrying a pin229. The. pin. 229 actuates a sine bar 230 having a-slot 23I into whichthepin 229 extends. The movement of the elevation disc 2.28 correspondsto the elevation of the gun E9 and the movement of. the sine bar 230corresponds to sin-E9. This movement is fed into a multiplier 235 whichis similar in construction to the multiplier I and has an input rack 236actuated by a pinion 231 through gears 238., shaft239, gears 240, shaft250 and pinion 25I from the cosine rack MI. The movement of the rack 236accordingly represents so cosine By. This movement is multiplied in the.multiplier 235 by the movement of sine bar 230 which represents sin.Eg,.to produce a movement. of the rack 255 which corresponds to. S0 cos Bgsin Eg, which movement is transferred by pinion 2.56, shaft 251,bevelledg'ear's 25.8, shaft. 259, bevelled gears. 260, shaft 26I andpinion 262. to rack 263 of a differential arm 264... The opposite endofthe differential arm 264 is connected by a pin 265 to.'a link 268which is actuatedlby the hydraulic rate amplifier valve to be describedto have a longitudinal movement corresponding to the rate of elevation0112. The output of the differential arm 264 istakenthrough a link 268which is pivoted at. an intermediate. point of the arm 264 and whichaccordingly has a movement which represents dE-So. cos Bg' sin Eg. Thismovement positions. an input arm 2.10 of a multiplier 21I, wherein itmultiplied by the time of flightv T. This is accomplishedby an inputrack 212 driven by a pinion 2.13 on the range shaft I11. The rack 212 isprovided with a T-arm 215 having a slot 216 engaging a pin 211 slidablymounted on the arm 210. The pin 211 engages a slot 218 in an outputarm219 having a rack 280. Movement of the rack 280- accordingly representsT('dE=-'So cos By sin Eg) which is Equation 2 for. the verticaldeflection Us to be applied to the gun. This deflection is taken fromthe rack 280 by the pinion 28I, shaft 282, bevelledgears 283, shaft 284,and bevelled gears 285 to a shaft 286 associated with the elevationfollow-upvalve to be described and thereby sets into the shaft 286 amovement corresponding to the calculated vertical deflection Us.

An elevation dial 288 which is visible from the front of the box 40, asshown in Fig. 1, is mounted on a shaft 289, Fig. 5, driven by a wormgear 296 from a worm 29'I carried on the elevation shaft 220.

Gyrvcontrol apparatus The gyrocontrol apparatus illustrated in Fig. 6is. of the general type disclosed in the copending application ofWilliam H. Newell, Ser. 503,510, filed Sept; 23, 1943, forGyroscopically ControlledOptical Mechanism. This mechanism comprises-agyroscope 300 of standard construction including a casing which isattached by trunnions 30-I to a, train gimbal frame 362 and by avpivoted bail 303 to; an. elevation gimbal 304.

'The elevation gimbal 304 is mounta ty trun- 'n'ions 305 in a bracket306-which is fixed to a pedestal'301 attached to the' box'40.fljhe-tra'in gimbal frame 302 is pivotally mounted at "its lower end inthe pedestal 301 and at "its upper end in the box 40 for rotation aboutavertical axis. The bail 303 is connected to the elevation gimbal 304 bya pin 308.

able in opening by means of an arm 315 to which I a link 316 ispi'votally attached. v p w The link 316 is also pivotally attachedto 'anarm 31'! carried by a shaft 318 'vvhich is connected through bevelledgears 319, shaft 320and pinion 321 to a rack 322 which constitutes theoutput element of a range 'divider mechanism 323. One of the inputelements of the range divider 323 comprises an L shape'd member 324having as one leg the rack I32 which is driven by the pinion [-51 of therange shaft 150 (Fig. and having as the other leg at horizontal-arm 325provided with a slot 326 within which a pin 328 slides. The pin 328 iscarried on a sleeve 329 which slides on a pivoted arm 330 connected tothe rack 322. The other input member to the range divider comprises arack 335 having a vertical arm 333 provided with a slot 331 in which thepin 32% slides. The rack--335 is actuated to represent target size by apinion 3410 mounted on a shaft 3 11 which is adjusted through bevelledgears 332 by means of a shaft 343 and an adf justing knob 353 which isaccessible from the front of the box 40 as shown in Fig. 1. A targetsize dial 345 is driven by the shaft 341 through bevelled ears 343. Thedial 345 is alsovisible from the front of the box 40 as shown in Fig. 1The adjusting knob 344 is adapted'tobe adjusted in accordance with theknown size of the target.

It is well known that with a stadia type range finder the range of thetarget is proportional to the width or size of the target divided by thesubtended angle. The divider mechanism 323 performs this division. Theposition of the rack 322 represents the angle subtended by the'target.The opening of the iris 314 is controlled from rack 322 to beproportional to the position of rack 322. The position of the rangeshaft its is adjusted by the gunner so that the image of the iris whichhe sees just encompasses the target. Having set the proper target sizeor width on the dial 345 the correct range will be introduced into thecomputing mechanism by shaft I60. For short ranges the time of flightmay be considered as proportional to the range. Therefore, the valueintroduced into the deflec tion computing mechanism by shaft 160 may beconsidered as representing time of flight T.

Immediately above the collimator is a mirror 350 mounted on trunnions353 by which it is pivoted to the train gimbal frame 302 in bushings 351for tilting movement about a horizontal axis and controlled by an arm352 which is attached to one of the trunnions 353. This mirror ispartially silveredso as to be transparent and at the same time toreflect rays strikil g-itfrom the col-.- limator lens system 312. Themirror 350 is 'infcved by the gyroscope 300 througha linkage comprisinga link 3'55 pivotally connected to the arm 352 andto arm 356 of equallength. Arm 356 constitutes 'one arm of a bell crank lever having-asecond arm 351. The bell crank lever ispivoted on a trunnion 3'58mounted on the frame 302andisactuated by a pin 3'53 engaging aj slot inthe end of arm 351 and carried on an arm 361 attached to thetrunnion 301of the "gyro-housing. The arm36l is equal in length 'to the spacingbetween the gyro-trunnion 301 and-the bell crank trunnion 358. By thisarrangement the tilting movement of the gyrohou'sing about a horizontalaxis produces a pivbtal'movement of the mirror350 through onehalf oftheangle of movement of the gyroscope, so that the rays'from the collimator310 as reflected by the mirror always remain parallel to thespin axis ofthe gyroscope. v The prjecessing force for causing the, yroseopej300 toprecess in elevation is applied throu h the shaft 364' of a hydraulicelevation precesing motor 355 to be described having an arm f3fi6'attached to a link 3151 which, in turn, is attached to an arm 368carried by the train -gimbal "frame 302.

The train precessing force is applied by, a train 'pre'ces'sing motor310 to be described, through a shaft 311, bevelled gears 312, shaft 313,arm 310, link 315 and arm 316 which is attached to the elevation gimbal30 4. v

Movement of the train gimbal frame 302 in train which corresponds tomovement in train bfthe spin axis'of the gyro 300, is transferred by thelink 361 to an arm 380 attached to the hydraulicfollow up valvemechanism to be described. Movement of the spin'axis of the gyro 390 inelevation is transferred from the elevatiori gimbal 304 through theshaft 313 and bevelled gears 381 to the elevation follow-up valvemechanism to be described. The mirror 350 is positioned in an upperprojection of the box 410 in the line of sight of the observer as in-(heated in Figs. 1 and 2.

Hydraulic system The-hydraulic mechanism is shown in Figs. 10 to 15. Theprecessing control pressures are generated hydraulically by the controlvalves in valve block 51 shown in Figs. 1, 10 and 11. Referring to'Figs. 11, 12, 13 and 18, the control handles 55 which are'actuated bythe gunner are shown as mounted on a horizontal shaft 450 which ispivoted in the bracket 55 for rotation about a horizontal axis'andcarries an arm 40!, Fig. 13, which is attached by a pivoted link 402 toa slidable rod 403 which is located within the bracket 58 and carriesa'pair of collars 400 which actuate an arm 405carri'e'd by a shaft 405.The shaft 053 in turn carries an arm 401 which is connected by a link408 to a valve'plunger 409 in a manner such that the valve pl'unger'isshifted from a central position an amount corresponding to therotational movement of the handles 55 about their horizontal axis. Theposition and rate of movement of the valve plunger 409 controls theoperation of an elevation 'precessing pressure generating valve 410. Therotational position of the handles 55 corresponds to the elevationprecession rates which are to be set up in the gyroscope 300, since, aswill be explained; the position and rate of movement of the plunger 453'controls and is a measureof the preces'sing pressure which is'generatedby the valve 310 for actuating theeleva tionprec'essing' motor; Thepressures thus gen: erated are controlled primarily in accordance 11with the position of the handles 55 but these pressures are modifiedsomewhat due to the rate of movement of the handles.

Rotation of the handles 55 and shaft 400 about a vertical axis causesthe bracket 56 to rotate and, in turn, to rotate a segment of a bevelledgear 4 l 2 which, through a bevelled rack 4l3 actuates a shaft 414carrying anarm-4I5 which is attached by a link 416 to a valve plunger418 which controls the operation of the train precessing pressuregenerating valve 420. The elevation precessing pressure generating valve4!!) and the train precessingpressure generating valve 420 are similarin construction and are adapted to generate pressures corresponding tothe axial displacement and rate of Y movement of the valve plungers 409and M8 respectively.

FIGURE 11 Referring first to the valve M0, the block 51 is formed with avalve chamber 425 in which slides a sleeve 426. The plunger 409 slidesaxially within a bore in the sleeve 426. The sleeve 426 is provided withend surfaces forming with the respective ends of the chamber 425,pressure chambers 421 and 428 respectively. The chamber 421 is suppliedwith fluid from a constant pressure P1 through a supply duct 429. Theduct 429 contains an adjustable restriction formed by the adjustingscrew 434, the end of which enters and partially closes the duct 429.The chamber 429 contains fluid under a pressure which is determined bythe position and rate of movement of the sleeve 426 and whichconstitutes the elevation precessing pressure Pe which is supplied bypassage 430 to a duct 43!. The end surfaces of the sleeve 426 arerecessed to receive compression springs 432 and 433 which are seatedwithin the chambers 421 and 428 respectively and serve normally to holdthe sleeve 426 balanced in its mid position, in which event the pressurein the chamber 428 will correspond to the pressure within the chamber421. Chamber 428 communicates through a passage 440 with'an annularchamber 44l formed in the plunger 409. Passages 442 and 443 in thesleeve 426 terminate at the plunger 409 on opposite ends of the chamber44! so that these passages are normally closed by the plunger 409 whenthe plunger is in the center position as shown, but are respectivelybrought into communication with the chamber 428 through the chamber MIand the passage 440 when the plunger 409 is shifted in one direction orthe other from its center position. The passag-e 442 communicates withan annular chamber 445 formed around the periphery of the sleeve 426 andthe passage 443 communicates with an annular chamber 446 similarlyformed in the sleeve 426. The chamber 445 receives fluid under aconstant pressure P2 which is double the pressure P1 and is suppliedthrough a passage 441 in the block 51 which communicates with a supplyduct 448 receiving fluid under the pressure P2 from a suitable source tobe described. The chamber 446 contains fluid under a low or zeropressure P which may constitute the intake pressure of the pump. Thechamber 446 communicates through a passage 449 with a return duct 450which leads to the supply reservoir of the pump.

The pressure P1 is supplied by a P1 generator valve 455 formed in theblock 51 and comprising a chamber having a slide 456 provided with endsurfaces451 and 458 forming end chambers 459 and 460 respectively. Theend surface of a passage 462.

12 451 is formed with-one half of the area of the end surface 456 sothat when the slide 456 is in balanced position the pressure within thechambar 460 Will be half that Within thechamber 459.

The chamber 459 is connected to the passage 441 containing fluid underpressure P2 by means The slide 456 is formed with an annular chamber 463which communicates through a passage 464 with the passag 429 to supplyfluid under the pressure P1 thereto. The annular chamber 463communicates with the chamber 460 by means of a passage 465 in theslide.

The slide 456 is provided with a reduced diameter end portion 410terminating at the surface 451 above mentioned and has an annular endsurface 41! surrounding the end portion 410. This annular surface 41!forms with an intermediate end wall of the valve chamber an annularchamber 412. The annular chamber 412 communicates through a passage 413with the passage 449 containing fluid under return pressure P0. Thepassage 413 terminates at the slide 456 adjacent one end of the chamber463 so that it is normally closed by the slide. A passage 415communicates from the passage 462 to the valve chamber on the oppositeend of the annular chamber 463 so that when the slide 456 is in its midposition the passages 415 and 413 are both closed. The fluid pressuresin the two end chambers 459 and 460 are then balanced and, du to thedifferences in area of the end surfaces, the pressure P1 is generated atexactly one-half of the pressure P2. If the pressure P1 should, however,vary from this amount, the pressure within the chamber 460 wouldlikewise vary, thereby unbalancing the slide 456. If the pressure in thechamber 460 is reduced, for example, the pressure P2 in the chamber 459causes the slide 456 to move upwardly, thereby establishingcommunication from the passage 415 through the chamber 463 to thepassage 465, thereby introducing fluid from the passage 415 into thepassage 465 and increasing the pressure in the latter passage. Thepressure will thus be built up until the pressures in the chambers 459and 460 are again balanced at which time the slide 456 returns to itsmid position and cuts off further fluid from the passage 415.

If, on the other hand, the pressure within the chamber 460 increases,the slide 456 will be forced downwardly establishing a communicationfrom the passage 465 through the chamber 463 to the passage 413, therebybleeding ofi some of the fluid within the passage 465 into the returnduct 450. This will likewise continue until the pressure in the chamber460 is reduced to P1, at which time a balance is again established. Inthis way the pressure in the passage 464 is maintained at exactlyone-half of the pressure P2 in the duct 446.

OPERATION OF FIG. 11

In the operation of the elevation precessing pressure generating valve410, beginning with the valve plunger 409 in the position shown, thepressure in the chamber 428 is exactly balanced against the pressure P1in the chamber 421. The precessing force Pe accordingly is the same asP1. If now the gunner rotates the handle about the horizontal axis forproducing a precessing rate in elevation, the valve plunger 409 will bemoved axially in one direction or the other. Assuming, for example, thatthe plunger 409 is moved upwardly, the chamber 4 is brought intocommunication with the passage 442 and

